Shock transmitting structure in an electromagnetically operated switch

ABSTRACT

A structure for supporting the electromagnet in an electromagnetically operated switch. The structure includes a metal shock plate which provides a mounting for the electromagnet and in turn is mounted on four posts that extend from a surface of the base of the switch whereon the stationary contacts of the switch are mounted. The shock plate provides a mounting for a molded part which encloses the switch contacts so that part is spaced from the base. Thus easy access to the contacts is obtained when the shock plate is removed from its position on the four posts and the shock generated by the energization of the electromagnet is transmitted through the four posts to the base when the shock plate is mounted on the four posts.

United States Patent Stallman .et al.

SHOCK TRANSMITTING STRUCTURE IN AN ELECTROMAGNETICALLY OPERATED SWITCH James E. Stallman, Whitefish Bay; Don J. Arneberg, Milwaukee, both of Wis.

lnventors:

U.S. Cl ..335/ 132 Int. Cl. ..H0lh 50/00 Field of Search ..335/132, 202, 193

References Cited UNITED STATES PATENTS Conner et a1. .335/ 193 Marien ..335/202 1 Feb. 15, 1972 Primary ExaminerHarold Broome Attorney-Harold J. Rathbun and William H. Schmeling [57] ABSTRACT A structure for supporting the electromagnet in an electromagnetically operated switch. The structure includes a metal shock plate which provides a mounting for the electromagnet and in turn is mounted on four posts that extend from a surface of the base of the switch whereon the stationary contacts of the switch are mounted. The shock plate provides a mounting for a molded part which encloses the switch contacts so that part is spaced from the base. Thus easy access to the contacts is obtained when the shock plate is removed from its position on the four posts and the shock generated by the energization of the electromagnet is transmitted through the four posts to the base when the shock plate is mounted on the four posts.

9 Claims, 3 Drawing Figures PAIENTEUFEB 15 m2 sum 1 [1F 2 \8 F II a 6 all w w m n INVENTOR JAMES E. STALLMAN DON J. ARNEBERG M SHOCK TRANSMITTING STRUCTURE IN AN ELECTROMAGNETICALLY OPERATED SWITCH The present invention relates to electromagnetically operated switchingdevices and particularly to a'structure for supporting an electromagnet in an electromagnetically operated switch.

- Electromagnetic switching devices, of the type with which the present invention is concerned, are commonly known as contactors and are-furnished as switching units of various sizes, having ratings which are normally in accordance with the standards promulgated by the National Electrical Manufacturers Association, commonly known as NEMA.- Among the commercial requirements which a contactor is required to satisfy are that the contactor must beconstructed so it can be easily mounted and wired on a panel and that the parts of the contractor be arranged so it is easy to inspect and replace the various components, such as the switching contacts and coil of the contactor while the contactor is wired on the panel.

In larger sized contactors, i.e., a NEMA Size5 contactors which are rated to carry 300 amperes or less, a magnet of considerable size and weight is required to exert the force required to cause a proper engagement between the movable and the stationary contacts of the contactor. Thus from a design standpoint, the relatively heavy magnet in the contactorshould be located as close as possible tothe panel. However, present commercial requirements dictate'that the most desirable form of a contactor should have its line or supply wireconnections at-the top of the device and the load wire connections at the 'bottom of the device to providean arrangement which is commonly termed as straight-thru wiring.

Further, the commercial requirements dictate that the wire connectingterminals be freely accessible and located as close to the panel as electrical clearance requirements will permit. Thus, if a contactor is to have a simple economical construction, a minimum size for its rated capacity and is to include a straight-thru wiring'-feature,the design requirements dictate that it is impractical to mount the magnet portion of the contact directly on the panel. Therefore, in the device according to the present invention, the magnet is carried forwardly of the base which supports the stationary contacts and wire connectin'g'terminals'so-that the device may be readily wired on the panel with straight-thru wiring and may be readily disassembled to permit the movable and the stationary contacts to be serviced; Further, in the contactor according to the present invention, the magnet armature is arranged to move toward the base when the electromagnet is energized to provide an economical simplified contactor structure. As the contactor construction herein described is'intended for the-larger size NEMA rated devices, it necessarily includes a relatively heavy armature which generates a considerable impact shock when the electromagnet is energized. The undesirable effects of the impact shock are minimized by a structure which includes a shock plate which supports the electromagnet and is mounted on .four sturdy posts-that extend from the molded base of the contactor. The four postshave inserts'molded therein which extend to the mounting panel so that the shock accompanying theengagement between the armature and stationary magnet part is directly transmitted to the mounting panel and ineffect bypasses the base. Further, a molded barrier which encloses the contacts-so as to isolate the poles of the contactor from each other and ground is suspended from the shock plate so as to be out of engagement with the base. Thus the shock is not transmitted through the barrier to the base and the inspection and servicing of the contact structure is readily accomplished by'merely removing the screws securing the shock plate to the posts so that the entire assembly, including the electromagnet and barrier, may be removed to make the contacts of the structurereadily accessible.

It is an object of the present invention to support an electromagnet structure of a contactor on a metal shock plate which is supported on posts which extend forwardly of a molded base carrying the stationary contacts of the contactor and to suspend a molded arc suppressing barrier'that encloses the contacts of the'shock plate so the-barrier is spaced from the base to prevent the shock which accompanies the engagement of the magnet armature with the stationary magnet part from being transmitted through the barrier to the base.

A further object is to provide a contactor with a structure in which a metal'shock plate provides a mounting for the electromagnet-and a molded arc suppressing barrier and to mount the shock plate'on four posts that extend from a mounting panel of the contactor forwardly of afront face of a molded base so the shock which is generated when the electromagnet is energized is transmitted through the shock plate and posts to themountin g panel.

Another object is to provide a contactor with a structure in which a metal shock plate mounted on four posts that extend forwardly on a front face of a molded base that carries the stationary contacts of the contactor provides a mounting for the electromagnet so that the shock generated when the electromagnet is energized is transmitted through the posts to a panel.

An additional object is to provide a contactor with a structure in which a metal shock plate provides a mounting for the electromagnet and a molded arc suppressing barrier and to mount the shock plate on four posts that extend from a mounting panel of the contactor forwardly of a front face of a molded base so the shock, which is generated when the electromagnet is energized, is transmitted through the shock plate and posts to the mounting panel and to mount the movable contacts of the contactor on a molded movable contact carrier that has a portion movable in a slot in a rear wall of the base so that the movable and stationary contacts are fully exposed and accessible when'the shock plate, including the electromagnet and barrier which are assembled on the shock plate, is detached from the posts.

1 Further object s and features of the invention will be readily apparent to those skilled in the art from the specification and appended drawings illustrating a preferred embodiment i which:

FIG. 1 is a perspective view showing as detached a base assembly and a magnet assembly of a switch that incorporates the features of the present invention.

FIG. '2 is a cross-sectional view taken along line 2-2 in FIG.

-1 with the magnet assembly secured to the base assembly.

FIG. 3 is a cross-sectional view taken along line 33 in FIG. 1 with portions of a shock plate for the switch shown as broken away.

For the. convenience in description, the electromagnet switch or contactor is described herein as disposed in a horizontal position when the contactor is mounted on a front wall of a vertical panel, the parts of the contactor being described in relation to'this position. Accordingly, the terms front and rear, upper and lower, vertical and horizontal and the like are not absolute but merely define 'more readily the relative positions of portions of the parts and their relative positions to each other when the contactor is mounted on a panel.

Referring to the drawings, there is shown as partly disassembled, an electromagnetic switch assembly 10 having a plurality of components'that are stacked one upon the other. The components of the assembly 10 include a metal mounting plate 12, an insulating base 14, an insulating barrier 16, a shock plate 18, an electromagnet assembly 20, a cover 22 and a movable contact carrier 24. The details of construction of the electromagnet assembly 20, as well as the arrangement for maintaining the electromagnet assembly 20 assembled in the switch are disclosed in an application for patent having a Ser. No. 99614, concurrently filed herewith. Similarly, the constructional details of the cover 22 and the arrangement for connecting the armature of the electromagnet assembly 20 to the contact carrier. 2f} are respectively shown in applications for US. Pat. Ser.-Nos. 99573 and 99574, respectively, which are similarly concurrently'filed herewith.

The metal mounting plate 12 is formed as a stamped metal part to provide a means to secure the switch assembly 10 to a vertical panel and the like, not shown. When the plate 12 is secured to the panel, an edge 26 becomes the bottom edge of the plate 12 and a surface 28 the front surface of the plate 12. The plate 12 has a pair of rearwardly extending indentations 30 along its bottom edge 26 that provide a pair of spaced mounting feet having openings therein. The plate 12 also has an indentation 31 at its top edge which provides an elongated mounting foot having an opening therein which together with the indentations 30 are provided for the purpose of securing the plate 12 to a vertical panel.

The switch 10, as shown in H0. 1, is a three-pole device in that is capable of completing and interrupting a three-phase circuit when the switch is actuated and deactuated. To ena-' ble the switch 10 to function as a three-pole device, the base 14 is furnished with three sets of stationary contacts and movable contacts. The base 14 and the barrier 16 are formed of a molded insulating material having arc suppressing capabilities and cooperate with each other to provide three compartments which extend in parallel between the top and the bottom of the switch 10. Positioned in each compartment is a set of stationary contacts and a movable contact. The base 14 has a rear surface 32 and a front surface 34. Extending into the material of the base forwardly of the rear surface 32 and through the sidewalls of the base 14 is a slot 36. The slot 36 is centered in a centerline equidistant between a top wall 38 and a bottom wall 40 of the base 14 and is exposed to each of the compartments in the base 14 by a passage 42. Positioned on opposite sides of the passage 42 so as to be equidistant from a vertical plane through the center of the passage 42 in each of the compartments is a pair of stationary contact assemblies 44 and 46 which are identical. Each of the assemblies 44 and 46 includes a terminal member 48 which is arranged to accept a bared end of a wire conductor, a conducting bar like member 50 and a support for a noble metal piece that provides a stationary contact surface 52. The members 48 and 50 are positioned on the front surface 34 by a screw 54 which extends through openings in the members 48 and 50 into a threaded insert which is embedded in the front surface 34. The support for the contact surface 52 is secured to the member 50 by a screw 56 and is shaped so the contact surface 52 is inclined and faces the vertical plane through the center of the passage 42.

The movable contact carrier 24 is generally U-shaped, having a bight or body portion 58 received so as to be movable in the slot 36 and arm portions 60 extending externally of the sidewalls of the barrier 16. The arm portions 60 are connected to an armature 62 of the electromagnet assembly and are moved rearwardly toward the plate 12 when the electromagnet is energized so that the bight portion 58 is moved rearwardly in the slot 36. At least one pair of compression springs 64, positioned between the rear wall of the bight portion 58 and the plate 12, cause the bight portion 58 to be positioned forwardly in the slot 36 when the electromagnet assembly 20 is deenergized.

' Extending through each of the passages42 is a projection 66. Each of the projections 66 is rectangular in shape and provides a mounting for a movable contact 68 and a spring biased releasable retainer 70 for the movable contact 68 in a manner fully disclosed in an application for US. Pat. Ser. No. 99612 concurrently filed herewith.

The movable contact 68 has a central portion positioned by the retainer 70 and a pair of inclined arms which extend generally in opposite directions from the central portion. Each of the inclined arms has a noble metal portion secured thereon to present contact surfaces72 which engage the contact surfaces 52 when the movable contact carrier 24 is moved rearwardly toward the plate 12 upon the energization of the electromagnet 20. When the carrier is at its furthest rearward position, the central portion of the-movable contacts 68 will be separated from the projections 66 and the force provided by the spring on the retainer 70 will cause the contact surfaces 52 and 72 to be pressed into a firm engagement with each other.

Extending forwardly from the front surface 34 on the base 14 are four spaced posts 74 each of which has a front surface 76 that is spaced'from the front surface 34. The posts 74 as illustrated are integral with the remainder of the base 14, although they may be formed as separate elements, if desired. Each of the posts 74 includes a metal insert 78 that has a' rear end 80 flush with the rear surface 32 and extends substantially throughout the molded material of the post 74 to a front end 82. The front end 82 is spaced slightly rearwardly of the front surface 76 to permit the base to be molded by economical molding practices. Extending forwardly from the rear end 80 and rearwardly from the front end 82 respectively in the inserts 78 are threaded bores 84 and 86. The threaded bores 84 in the inserts 78 contained within the four posts 74 are aligned with four raised support surfaces 88 on the plate 12, each of which has an opening therein aligned with the bore 84. The rear surface 32 and the ends 80 are positioned on the support surfaces 88 to mount the base 14 on the plate 12 when four screws 90 are tightened into the bores 84 so that the only areas of engagement between the base 14 and the plate 12 occur in those areas where the rear surface 32 engages the support surfaces 88.

The shock plate 18 is formed as a metal plate having a thickness so that it will resist permanent deformation when it is mounted on the surfaces 76. The posts 74 extend from the front surface 34 so two of those posts 74 are below and two of the posts 74 are above a horizontal plane that is normal to the surface 34 through a centerline passing through the slot 36. The shock plate 18 has a front surface 92 and a rear surface 94 and four openings 96 located therein to be aligned with the threaded bores 86 within the four posts 74 when the rear surface 94 is positioned on the front surfaces 76. The shock plate 18 is mounted on the front surfaces 76 in spaced relation to the front surface 34 by four screws 98 which pass through the openings 96 and are threaded into the threaded bores 86. The shock plate has an additional four spaced openings which receive four screws l00-to mount the barrier 16 on the rear surface 94. The barrier 16 has suitable inserts molded therein which receive the screws 100 to mount a front wall 102 of the barrier 16 on the rear surface 94 so the barrier 16 in effect is suspended on the shock plate 18. The barrier 16 further has a pair of partitions 106 integrally formed therewith which extend rearwardly from the front wall 102 to bottom edges 108 which are received in grooves 110 in the front surface 34 to provide the three compartments wherein the stationary and movable contacts are received. The bottom edges 108 as well as the bottom edges 112 of the side and the .top and bottom walls of the barrier 16 which from the rear side of the barrier extend so that all of the bottom edges 108 and 112 are spaced forwardly of the front surface 34 and hence the entire rear side of the barrier 16 is spaced from the base 14 when the barrier is suspended on the shock plate 18.

The electromagnet assembly includes the armature 62, a stationary magnet 114, a magnet coil 116 and a means for mounting the stationary magnet, the armature and the magnet coil on the front surface 92 which is disclosed in the application for US. Pat. Ser. No. IC-5l9, supra. The means for mounting the electromagnet assembly on the front surface 92 of the shock plate 18 includes a retainer 118 that is formed of a pair of metal parts and an elastomeric shock pad 120 which is positioned between the stationary magnet 1 l4 and the front surface 92. The retainer 118 positions the stationary magnet 114 and the coil 116 on the front surface 92 so the armature 62 is required to move along the plane that is normal to the front surface 34 toward the shock plate 18 to engage the pole faces of the stationary magnet 114 when the magnet coil is energized. The cover 22, which is secured to a top end of the barrier extending forwardly of the shock plate 18 by four screws 122, positions the magnet coil 116 on the shock plate 18. The free ends of the arms 60 of the movable contact carrier 24 are secured to the armature 62 by a means including a pair of screws 124. The contact carrier is guided in its movement in a manner disclosed in the application for US. Pat. Ser. No. 99614, supra.

The switch also includes a suitable arc suppressing means that includes a plurality of arc plates 126 which are secured to the barrier 16 and operate in a manner well known to those skilled in the art. Access to the stationary and movable contacts of the switch 10 is readily obtained by removing the four screws 98 and the pair of screws 124 so that the assembly, including: the shock plate 18, the barrier 16, the electromagnet assembly 20, as well as the cover 22, is removed as a unit from the base 14 while the movable contact carrier 24 remains assembled with the base 14. The removal of the shock plate 18 and the components thereto will expose the front wall 34 and the stationary contacts assemblies 44 and 46 as well as the movable contacts 68 for inspection. The replacement of the stationary contacts is readily accomplished by removing the screws 56 and the supports for the stationary and contact surfaces 52 and substituting new supports and replacing the screws 56. The replacement of the movable contacts is readily accomplished in a manner described in the application for US. Pat. Ser. No. 99612, supra.

When the switch 10 is mounted on a vertical panel and the magnet coil 116 is energized, the movable armature 62 will move toward the panel into engagement with the pole faces of the stationary magnet 114. The shock accompanying the engagement between the armature 62 and the stationary magnet 114 is transmitted through the shock pad 120 to the shock plate 118 and is prevented from being transmitted through the barrier 16 to the base 14 because of the spacing between the rear edges of the barrier 16 and the front surface 34 of the base 14. Further, the only areas of contact between the rear surface 32 on the base 14 and the front surface 28 on the plate 12 occur at those areas where the portions of the base engage the support surfaces 88. Thus the base 14 and the support plate 12 in effect are spaced from each other and the shock is transmitted from the shock plate 18 through the posts 74 directly to the support surface 88 of the plate 12 and not through the base 14. In this connection the inserts 78 aid in providing support and shock transmitting means as well as add strength to the posts 74.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In an electromagnetically operated switch, the combination comprising: an insulating base having a front surface and a rear surface, an assembly including a metal shock plate, an insulating barrier and an electromagnet assembly, said shock plate having a front side and a rear side, said insulating barrier having a front wall secured to the rear side of the barrier, a rear side and a plurality of spaced walls extending rearwardly from the front wall to the rear side cooperating with the front surface of the base to define a plurality of spaced compartments, said electromagnet assembly having a stationary magnet, a magnet coil, a movable armature and means for mounting stationary magnet, the armature and the magnet coil on the front side of the shock plate so the stationary magnet part is supported by the shock plate and the armature is movable along a plane normal to the front surface of the base toward the shock plate into engagement with the stationary magnet part when the magnet coil is energized, a pair of stationary contacts mounted on the front surface of the base in each of said compartments with the contacts of each pair disposed equidistantly on opposite sides of the plane, a movable contact in each compartment having portions extending on opposite sides of the plane, means for guiding the armature in its movement in said plane and causing the movable contacts to engage the pairs of stationary contacts in the respective compartments when the magnet coil is energized, and at least one pair of posts extending forwardly of the front surface of the base to provide support surfaces on opposite sides of the plane that are spaced forwardly from the front surface of the base so the entire rear side of the barrier is spaced from the front surface of the base when portions of the rear side of the support plate are mounted on the support surfaces whereby the shock accompanying the engagement between the armature and stationary magnet part is transmitted'through the shock plate and posts when the shock plate is mounted on the surfaces and for exposing the movable contacts and the stationary contacts when the assembly including the shock plate is detached from the posts.

2. The combination as recited in claim 1 wherein two pairs of posts provide a pair of spaced supports on each side of the plane for the shock plate.

3. The combination as recited in claim 1 wherein the posts are integral with the base.

4. The combination as recited in claim 3 wherein each of the posts has a metal insert embedded therein having a threaded bore which receives a screw extending through an opening in the shock plate.

5. The combination as recited in claim 4 wherein the insert in each of the posts extends to the rear surface of the base.

6. The combination as recited in claim 5 wherein the inserts extend substantially throughout the entire length of the posts.

7. The combination as recited in claim 2 wherein the means which causes the movable contacts to engage the stationary contacts includes a molded member that has a portion movable in a slot extending in the rear wall of the base.

8. The combination as recited in claim 7 wherein the posts are integral with the base and each of the posts has a metal insert embedded therein having a threaded bore which receives a screw extending through an opening in the shock plate.

9. The combination as recited in claim 8 wherein the inserts in each of the posts extend substantially throughout the entire length of the posts and to the rear wall of the base.

mg UNITED STATES PATENT OFFICE I CERTIFICATE OF QQRREQTEQN Patent No.- 31 31 9 Dated li 5, 9?

Inventor-(s) Jmes E It 115 certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 2, line 37,- cance1"i" and insert --in---.

C01. 4, line 26', cancel "those" and insert --the Col. 6, line 23, after "the" (2nd occurrence) insert "support-n Signed and sealed this 22nd day of August 1972 Attest;

EDWARD M FLETCl-lERJR. ROBERT GOTTSCHALK At test'ing Officer Commissioner of Patents UNITED swam PATENT om CER'UFICATE @F (IQRREEQTEQN Patent No.- 3, 3, 9 Dated Fgbruai? 59 95 Inventor(s) J mes E It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

001. 2, line 37, cancel "1" and insert ----in---.

C01. 4, line 26, cancel "those" and insert --the C01. 6, line 23, after "the" (2nd occurrence) imeer't --eupport fi Signed and sealed this 22nd day of August 1972.

(SEAL) Attest:

EDWARD M FLETcHERJR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

1. In an electromagnetically operated switch, the combination comprising: an insulating base having a front surface and a rear surface, an assembly including a metal shock plate, an insulating barrier and an electromagnet assembly, said shock plate having a front side and a rear side, said insulating barrier having a front wall secured to the rear side of the barrier, a rear side and a plurality of spaced walls extending rearwardly from the front wall to the rear side cooperating with the front surface of the base to define a plurality of spaced compartments, said electromagnet assembly having a stationary magnet, a magnet coil, a movable armature and means for mounting stationary magnet, the armature and the magnet coil on the front side of the shock plate so the stationary magnet part is supported by the shock plate and the armature is movable along a plane normal to the front surface of the base toward the shock plate into engagement with the stationary magnet part when the magnet coil is energized, a pair of stationary contacts mounted on the front surface of the base in each of said compartments with the contacts of each pair disposed equidistantly on opposite sides of the plane, a movable contact in each compartment having portions extending on opposite sides of the plane, means for guiding the armature in its movement in said plane and causing the movable contacts to engage the pairs of stationary contacts in the respective compartments when the magnet coil is energized, and at least one pair of posts extending forwardly of the front surface of the base to provide support surfaces on opposite sides of the plane that are spaced forwardly from the front surface of the base so the entire rear side of the barrier is spaced from the front surface of the base when portions of the rear side of the support plate are mounted on the support surfaces whereby the shock accompanying the engagement between the armature and stationary magnet part is transmitted through the shock plate and posts when the shock plate is mounted on the surfaces and for exposing the movable contacts and the stationary contacts when the assembly including the shock plate is detached from the posts.
 2. The combination as recited in claim 1 wherein two pairs of posts provide a pair of spaced supports on each side of the plane for the shock plate.
 3. The combination as recited in claim 1 wherein the posts are integral with the base.
 4. The combination as recited in claim 3 wherein each of the posts has a metal insert embedded therein having a threaded bore which receives a screw extending through an opening in the shock plate.
 5. The combination as recited in claim 4 wherein the insert in each of the posts extends to the rear surface of the base.
 6. The combination as recited in claim 5 wherein the inserts extend substantially throughout the entire length of the posts.
 7. The combination as recited in claim 2 wherein the means which causes the movable contacts to engage the stationary contacts includes a molded member that has a portion movable in a slot extending in the rear wall of the base.
 8. The combination as recited in claim 7 wherein the posts are integral with the base and each of the posts has a metal insert embedded therein having a threaded bore which receives a screw extending through an opening in the shock plate.
 9. The combination as recited in claim 8 wherein the inserts in each of the posts extend substantially throughout the entire length of the posts and to the rear wall of the base. 